Quick-change mechanism for a tie bar

Abstract

A quick-change tie bar mechanism includes an actuator having a rod coupled to a first bearing member and a body coupled to a second bearing member. The first and second bearing members are configured to reciprocally move in opposite directions in response to extension and retraction of the rod relative to the body. The bearing members have a first configuration for engaging a nut threaded on a tie bar to fix the tie bar in relation to a platen through which the tie bar extends. The first and second bearing members also have a second configuration for releasing the tie bar to permit removal through the platen so that a part may be accessed for removal and/or replacement.

What is claimed is:  
     
       1. An quick release holding mechanism to selectively fix a tie bar to a casting machine platen, the tie bar extending through an opening of the platen, comprising: 
       a base defining a hole to align with the opening, said base being configured for coupling to the platen;  
       a pair of rails connected to said base about said hole;  
       a first bearing member and a second bearing member slidably engaging said rails, one of said first and second bearing members including a bridge portion crossing another of said first and second bearing members, said first bearing member defining a first collar portion and said second bearing member defining a second collar portion, said first and second collar portions being positioned opposite one another between said rails and being aligned with said hole;  
       a pair of stops positioned opposite one another to limit travel of said first and second bearing members along said rails;  
       a hydraulic cylinder actuator including a body coupled to said first bearing member to travel therewith and a rod coupled to said second bearing member to travel therewith, said rod being positioned between said rails and being extendable and retractable relative to said body along an axis generally parallel to said rails in response to activation of said actuator to move both of said first and second bearing members in opposite directions and adjust distance between said first and second collar portions; and  
       wherein a first distance separates said first and second collar portions when said rod is in a first position and a second distance separates said first and second collar portions when said rod is in a second position, said second distance being greater than said first distance and said rod being extended further in said second position than said first position.  
     
     
       2. The mechanism of  claim 1 , further comprising an operator activated control coupled to said hydraulic cylinder. 
     
     
       3. The mechanism of  claim 1 , wherein said hydraulic cylinder is of a double-acting type. 
     
     
       4. The mechanism of  claim 1 , wherein said bridge portion of said one of said first and second bearing members moves past at least a portion of said another of said first and second bearing members when changing said rod between said first position and said second position. 
     
     
       5. The mechanism of  claim 1 , further comprising a pair of bridle members connected to said bridge portion to move therewith. 
     
     
       6. The mechanism of  claim 1 , wherein said rod is fixedly attached to said bridge portion.